"A planet that has a positive gravity"

[USS Triumphant]

In the TOS episode "Court Martial", Spock said, "if I let go of a hammer on a planet that has a positive gravity, I need not see it fall to know that it has in fact fallen." Which caused Christopher to post in a TOS forum thread recently:

"What's always gotten me about that line is the implication that there are planets with negative gravity. How could that happen? How would they even form?"

I suggested: "Spin acceleration greater than the gravity generated by the planet?", and "A strong electromagnetic core that pulls the pieces of the forming planet together despite the acceleration force from the spin? (Pieces would presumably be made of some element highly susceptible to magnetism.) Seems possible, but if I were the first starship captain to come across such a world, I would suspect artificial construction."

And now I've found this.

Anyone have any thoughts on these, or any other possible suggestions on how such a world could exist? I'm posting this in this forum because I'm not looking for Treksplanations ("Q did it") but actual scientifically supportable explanations for how this could work in the real universe.

 

[YellowSubmarine]

Obviously, Kirk was a computer programmer (in the prime timeline there was no hacker like Gaila to break the Kobayashi Maru test for him), so like any software developer he had developed the useful habit of taking care of exceptional situations even when they cannot ever occur. Give him a break, he was covering his ass just in case someone discovered a planet with negative mass somewhere in the future. Besides, in a universe where the impossible was seemingly happening, imagining all virtual possibilities might become a meme. So it is a case of us taking a figure speech from a different culture way too seriously.

I like that. May I join?

I don't think rotation is a good candidate. Not only it's distinguishable from genuine gravitation by the Coriolis effect on moving objects, but it doesn't repel outside objects. That is, objects on the surface might fly upwards, but any object not on the surface would act as if it was above a normal planet – it would be either in orbit, or on a trajectory to or away from the positive gravity well. The funny part that surface is either in orbit or in trajectory away from itself is only that – funny. Keeping orbit around that asteroid is as impossible as keeping orbit around an asteroid of the same mass that's not spinning. Similarly, on a fully-sized spinning-like-there's-no-tomorrow planet your hammer thrown down from orbit would fall down. And eventually hit the surface, even funnier things happening after that notwithstanding.

However, since this is a fictional show with time travel and... ahem... damn teleporters... I don't see why don't we simply go for the real thing – negative mass? Puts a tick in all the boxes: attracts itself, check, can form a planet, check, repels regular matter, check. A genuine gravity fountain. It is also mostly compatible with our universe except for a few energy conditions that would need some revision, so it works like a charm in fictional context. For all we know, it might even exist. (And so can wizards!)

The most significant advantage of negative mass over rotation is that it remains funny even after Friday.

 

[Kemaiku]

A shell world existing around an antigraviton producing metallic core with an exotic matter interior, a fragment of something that the core of the planet began to form around, pushing the other matter into a shell like layer at a fixed distance.

 

[PurpleBuddha]

How great would it be to discover negative gravity matter? It would do so much for us, starting with real hover-boards. That said, the universe being the little bitch that it is, if such a thing does exist it is probably also radioactive.

 

[Kemaiku]

Yeah, in real life the bosons that cause the fundemental forces seem to be entirely "neutral" in that regard. Gravity, magnetism and electrostatics work on matter and antimatter exactly the same way.

 

[JES]

Or it would take a lot of energy to reproduce the same effect.

 

[YellowSubmarine]

Yeah, in real life the bosons that cause the fundemental forces seem to be entirely "neutral" in that regard. Gravity, magnetism and electrostatics work on matter and antimatter exactly the same way.

Have we ever produced enough anti-matter to confirm that though? It might be true that any different result would be more incredible than the moon hatching, but until it's positively confirmed, we dreamers can expect miracles, can't we? Like I am still waiting to win the lottery even though I don't play the lottery.

 

[Kemaiku]

Yeah, in real life the bosons that cause the fundemental forces seem to be entirely "neutral" in that regard. Gravity, magnetism and electrostatics work on matter and antimatter exactly the same way.

Have we ever produced enough anti-matter to confirm that though? It might be true that any different result would be more incredible than the moon hatching, but until it's positively confirmed, we dreamers can expect miracles, can't we? Like I am still waiting to win the lottery even though I don't play the lottery.

Bubble chamber tracks would be the best way to determine that right now, positrons don't behave oppositely to the pull of gravity when produced. They also bend according to their charge, behave the same as electrons in terms of the absorption or emission of energy.

So gravity and photons, and basic electrostatic attraction, paths through the bubble chamber magnetic fields, all that's different is that positrons bend the opposite direction to electrons, according to their positive charge, which protons also do, the positrons spiral a lot more being so much smaller.

If we ever create an anti-deuterium atom, at least two nucleons, we'll know of the Weak and Strong nuclear forces also act the same, which they likely should.

 

[tomswift2002]

With gravity you have to remember that wherever you go in a solar system you are always going to be subjected to gravity, since without it the planets would not be able to maintain their orbits around the sun (even Pluto). So I always figured that the episode writer was looking for an easy way to explain gravity as here on Earth and null/micro-gravity, while still sounding scientific. Think about, the episode writer's even referred to a black hole as a black star since that was the terminology in use in the 1960's.

So I always took Spock's line as meaning that if he let the hammer go here on earth, he would not need to see it hit the ground to know that it had fallen. Whereas on Earth's moon, even with it's micro-gravity, the hammer would still, most likely, float away if he let go of it.

 

[Metryq]

Whereas on Earth's moon, even with it's micro-gravity, the hammer would still, most likely, float away if he let go of it.

Huh? "Float away"? By that I hope you mean "float" to the ground more slowly than on Earth, but I would hardly call one-sixth G "micro-gravity." The astronauts on Apollo 15 jokingly dropped a hammer (by coincidence) and a feather after Galileo's apocryphal experiment at the Leaning Tower of Pisa. Neither the feather nor the hammer "floated away."


And "it's" is a contraction, not a possessive.

 

[CorporalCaptain]

And now I've found this.

That is really cool.

 

[YellowSubmarine]

Actually, Hawking radiation implies the observation of negative energy. That's how black holes evaporate, they appear to gain negative mass. I have no clue what that actually means though.

 

[PurpleBuddha]

Actually, Hawking radiation implies the observation of negative energy. That's how black holes evaporate, they appear to gain negative mass. I have no clue what that actually means though.

Fucking radiation. I knew it.

 

[Timo]

Of course, it could all be in the semantics. "Zero level" need not mean zero gravity - it might be some "Greenwich meridian" of gravity instead, such as Earth's familiar one gee. Spock would be playing it safe: "If I see planet with more gravity than Earth, the hammer will fall. In theory, some planets might have so little gravity that a freak mishap might see the hammer floating away instead, so I'm specifically excluding that."

Timo Saloniemi

 

[Bisz]

Also, I do believe that gravitons are their own anti-particles, so I don't believe that we'll ever be able to "discover" anti-gravity in the sense that instead of pulling something (like a tractor beam) we'll be able to "push", like a floating car or the like. Not to say we won't find other ways to achieve that effect.